Alzheimer’s

Posted on Alzheimer's, Autism

Autism – How our brain decodes other people’s gaze

Through the eye of the beholder
Through the eye of the beholder

The direction of a person’s gaze is crucial in everyday social interactions. Our brain’s ability to quickly interpret this information is key for instant communication. A recent study published in the journal NeuroImage by a team from the University of Geneva (UNIGE) has provided new insights into how our brains detect gaze direction with unprecedented precision. These findings have significant implications for our understanding of autism.

Human faces are the most common and consistent visual stimuli that we encounter from the moment we are born. Our brains have developed the expertise to memorize and recognize faces and to interpret the messages they convey. For example, direct eye gaze signals a desire to engage in social interaction, while avoiding eye contact conveys the opposite message. However, there has been extensive research on how rapidly our brains can comprehend the gaze of others. Existing publications have mainly focused on studying the eye region in isolation, neglecting other factors like head orientation.


Cerebral analysis of gaze

A team from UNIGE introduced study participants to 3D avatars, each with different head and gaze directions. In the first task, volunteers were asked to indicate the orientation of the head, while in the second task, they had to identify the direction of the eyes. By analyzing brain activity using an electroencephalogram, the research team discovered that these two processes can be reliably decoded independently of each other.


“The experiment also shows a certain hierarchy in processing these two types of information. The brain first perceives the more general visual cues, such as the orientation of the head, from 20 milliseconds onwards, before focusing on the more specific information, such as the eyes, from 140 milliseconds onwards. This hierarchical organization then allows for the integration of eye region and head orientation information, ensuring accurate and effective judgment of gaze direction,” explained Domilė Tautvydaitė.


The study found that people were much more accurate at understanding where others were looking when they were specifically instructed to pay attention to the direction of their gaze. This shows that the context of a task affects how we perceive and interpret where someone is looking. According to Nicolas Burra, a senior lecturer at the Faculty of Psychology and Educational Sciences and director of the Experimental Social Cognition Laboratory (ESClab) at UNIGE, these results suggest that people are better and quicker at recognizing the intentions of others when they are actively engaged in a social interaction.


A cutting-edge method

The method used provides extremely accurate results for these two mechanisms. The research team integrated the analysis of neural activity using electroencephalography (EEG) with machine-learning techniques, allowing them to predict the decoding of gaze and head direction even before the participants were aware of it. Nicolas Burra adds, “This method represents a significant technical innovation in the field, allowing for a much more precise analysis than was previously attainable.”


In individuals with autism spectrum disorders, there may be difficulty in interpreting social cues, leading to a preference for avoiding eye contact. This is also observed in Alzheimer’s disease, where memory issues can impact relationships and cause social withdrawal. Therefore, it’s important to study the brain mechanisms involved in perceiving where others are looking.


The study results and the method used make a significant contribution to the early diagnosis of autism spectrum disorders in children. As Alzheimer’s disease progresses, one of the most striking symptoms is the inability to recognize faces, including those of family members.

Posted on Alzheimer's, Cognitive dysfunction

Protecting Your Brain Health – How Science Is Revolutionizing Cognitive Health

We’re living in a neuroscience revolution, with more ways to detect and treat brain disorders than was imaginable just a few decades ago. Hear from Dr Longo, a leading expert in the research and treatment of neurological conditions, about the work being done at Stanford to transform the field and offer hope to the millions of people suffering from cognitive impairment due to Alzheimer’s and other neurodegenerative conditions. From novel blood tests and brain imaging approaches to emerging treatments, Dr Longo will explain how he and his fellow scientists work to detect problems earlier, create strategies to delay the onset of cognitive loss, reverse impairment once it begins, and increase brain resiliency for all people. He’ll also offer information you can use, starting now, to help protect your own brain health far into the future.

Posted on Alzheimer's

Dementia fighter: Orienteering helps brain and body alike, with greater benefits for those who move quickest

Orienteering map

A new study finds orienteering helps both brain and body, with greater benefits for those who move quickest. CREDIT McMaster University

The sport of orienteering, combining exercise with challenging navigation, may be better for the brain than exercise alone, according to new research from kinesiologists at McMaster University.

In fact, the more vigorous the orienteering, the greater the benefits, which could be used to fight cognitive decline, dementia and catastrophic diseases such as Alzheimer’s.

The study, a follow-up to research published in 2023, examined the cognitive effects of orienteering at different intensity levels.

The researchers focused on orienteering because it requires athletes to navigate quickly through a series of checkpoints across an unknown terrain, using only a map and compass.

Through focused attention and deduction, orienteers use spatial information to make quick decisions while moving through a course. 

This form of navigation employs the hippocampus, an area of the brain more susceptible to age-related decline than others. Degeneration in this region can impair learning, memory and spatial cognition. 

“Remarkably, even a single orienteering session improved spatial memory in our study participants,” says lead author Emma Waddington, a graduate student in the Department of Kinesiology at McMaster who conducted the work with colleagues at Western University. “This suggests that participating in orienteering, even infrequently, could enhance spatial abilities, potentially delaying their decline with age.”

For the study, recently published in the journal PLOS One, groups of active, healthy young adults with no orienteering experience navigated a course on the McMaster campus, some by walking and others by running. A control group exercised vigorously without having to navigate. 

Using blood samples, researchers measured participants’ lactate levels, an indicator of exercise intensity, and brain-derived neurotrophic factor (BDNF), a promoter of brain plasticity. They tested memory performance before and after the sessions.

Researchers found that running increased lactate, BDNF and memory to a greater degree than walking, with particular benefits for spatial memory among those running while orienteering.

Losing the ability to find one’s way is among the earliest and most common symptoms of Alzheimer’s disease, which affects half of all afflicted individuals, even in the mildest stage of the disease.

“With no known cure for dementia, preventative measures that can help to stave off age-related cognitive decline are essential,” says Jennifer Heisz, Canada Research Chair in Brain Health and Aging at McMaster University, who supervised the research.

She says modern-day dependency on vehicles featuring navigation guided by GPS may mean that most people don’t use their wayfinding skills, possibly leading to spatial memory deficits and a diminished sense of direction, which orienteering could revive. 

The researchers say exploring the long-term effects of orienteering on human cognition and in different age groups is an important area for future study.

Posted on Alzheimer's, Autism

From autism to Alzheimer’s: A large-scale animal study links brain pH changes to wide-ranging cognitive issues.

From autism to Alzheimer’s: A large-scale animal study links brain pH changes to wide-ranging cognitive issues
From autism to Alzheimer’s: A large-scale animal study links brain pH changes to wide-ranging cognitive issues

A global collaborative research group comprising 131 researchers from 105 laboratories across seven countries announces a groundbreaking research paper submitted to eLife. Titled “Large-scale Animal Model Study Uncovers Altered Brain pH and Lactate Levels as a Transdiagnostic Endophenotype of Neuropsychiatric Disorders Involving Cognitive Impairment,” the study identifies brain energy metabolism dysfunction leading to altered pH and lactate levels as common hallmarks in numerous animal models of neuropsychiatric and neurodegenerative disorders, such as intellectual disability, autism spectrum disorders, schizophrenia, bipolar disorder, depressive disorders, and Alzheimer’s disease.

At the forefront of neuroscience research, the research group sheds light on altered energy metabolism as a key factor in neuropsychiatric and neurodegenerative disorders. While considered controversial, an elevated lactate level and the resulting pH decrease are now proposed as a potential primary component of these diseases. Unlike previous assumptions associating these changes with external factors like medications, the research group’s findings suggest that they may be intrinsic to the disorders. This conclusion was drawn from five animal models of schizophrenia/developmental disorders, bipolar disorder, and autism, which are exempt from such confounding factors. However, research on brain pH and lactate levels in animal models of other neuropsychiatric and neurological disorders has been limited. Until now, it was unclear whether such changes in the brain were a common phenomenon. Additionally, the relationship between alterations in brain pH and lactate levels and specific behavioural abnormalities had not been established.

This study, encompassing 109 strains/conditions of mice, rats, and chicks, including animal models related to neuropsychiatric conditions, reveals that changes in brain pH and lactate levels are a common feature in a diverse range of animal models of diseases, including schizophrenia/developmental disorders, bipolar disorder, autism, as well as models of depression, epilepsy, and Alzheimer’s disease. This study’s significant insights include:

I. Common Phenomenon Across Disorders: About 30% of the 109 types of animal models exhibited significant changes in brain pH and lactate levels, emphasizing the widespread occurrence of energy metabolism changes in the brain across various neuropsychiatric conditions.

II. Environmental Factors as a Cause: Models simulating depression through psychological stress, and those induced to develop diabetes or colitis, which have a high comorbidity risk for depression, showed decreased brain pH and increased lactate levels. Various acquired environmental factors could contribute to these changes.

III. Cognitive Impairment Link: A comprehensive analysis integrating behavioral test data revealed a predominant association between increased brain lactate levels and impaired working memory, illuminating an aspect of cognitive dysfunction.

IV. Confirmation in Independent Cohort: These associations, particularly between higher brain lactate levels and poor working memory performance, were validated in an independent cohort of animal models, reinforcing the initial findings.

V. Autism Spectrum Complexity: Variable responses were noted in autism models, with some showing increased pH and decreased lactate levels, suggesting subpopulations within the autism spectrum with diverse metabolic patterns.

“This is the first and largest systematic study evaluating brain pH and lactate levels across a range of animal models for neuropsychiatric and neurodegenerative disorders. Our findings may lay the groundwork for new approaches to develop the transdiagnostic characterization of different disorders involving cognitive impairment,” states Dr. Hideo Hagihara, the study’s lead author.

Professor Tsuyoshi Miyakawa, the corresponding author, explains, “This research could be a stepping stone towards identifying shared therapeutic targets in various neuropsychiatric disorders. Future studies will center on uncovering effective treatment strategies across diverse animal models with brain pH changes. This could significantly contribute to developing tailored treatments for patient subgroups characterized by specific alterations in brain energy metabolism.”

In this paper, the mechanistic insights into the reduction in pH and the increase in lactate levels remain elusive. However, it is known that lactate production increases in response to neural hyperactivity to meet the energy demand, and the authors seem to think this might be the underlying reason.

References

a. Halim ND, Lipska BK, Hyde TM, Deep-Soboslay A, Saylor EM, Herman M, et al (2008). Increased lactate levels and reduced pH in postmortem brains of schizophrenics: medication confounds. Journal of Neuroscience Methods 169(1): 208–213.

b. Hagihara H, Catts VS, Katayama Y, Shoji H, Takagi T, Huang FL, et al (2018). Decreased Brain pH as a Shared Endophenotype of Psychiatric Disorders. Neuropsychopharmacology 43(3): 459–468.

Posted on ADHD, Alzheimer's, Dementia

Adults with ADHD are at increased risk for developing dementia

Adults with ADHD are at increased risk for developing dementia
Rutgers researcher explores ADHD’s link to dementia and if risks can be mitigated with ADHD treatment

Adults with attention-deficit/hyperactivity disorder (ADHD) are nearly three times more likely to develop dementia than adults without ADHD, according to a Rutgers study.

The study, coauthored by Michal Schnaider Beeri, director of the Herbert and Jacqueline Krieger Klein Alzheimer’s Research Center at Rutgers Brain Health Institute (BHI) was published in JAMA Network Open. It followed more than 100,000 older adults in Israel over 17 years to examine if adults with ADHD are at increased risk for dementia, including Alzheimer’s disease.

Although more than 3 percent of the adult population in the United States has ADHD, there is limited research on this group.

“By determining if adults with ADHD are at higher risk for dementia and if medications and/or lifestyle changes can affect risks, the outcomes of this research can be used to better inform caregivers and clinicians,” said Beeri, the Krieger Klein Endowed Chair in Neurodegeneration Research at BHI and a faculty member of the Rutgers Institute for Health, Health Care Policy and Aging Research.

Using data from a national cohort study of more than 100,000 people who were followed from 2003 to 2020, researchers analyzed those with and without ADHD and the occurrence of dementia among the groups as they aged. Researchers found the presence of adult ADHD was associated with a significantly higher risk of dementia even when other risk factors for dementia were taken into account, such as cardiovascular conditions.

ADHD in adults may materialize as a neurological process that reduces the ability for them to compensate for the effects of cognitive decline later in life, researchers said.

“Physicians, clinicians and caregivers who work with older adults should monitor ADHD symptoms and associated medications,” said Abraham Reichenberg, a professor at the Department of Psychiatry at the Icahn School of Medicine at Mount Sinai and senior author of the study.

“Symptoms of attention deficit and hyperactivity in old age shouldn’t be ignored and should be discussed with physicians,” said Stephen Levine, a professor at the School of Public Health at the University of Haifa.

Additionally, the research suggests ADHD treatment incorporating psychostimulants may help reduce the risk of dementia in adults with ADHD as psychostimulants are known to modify the trajectory of cognitive impairment. But researchers said future studies should examine in more detail the impact of medications in patients with ADHD and how they could affect risk.